Global interrupts are enabled and the OVIF bit in the TCC0_INTFLAGS gets set when the timer overflows (every 1mSec). I can proove this by polling the OVIF bit from main and toggling an O/P pin.

The problem is the program never jumps to the interrupt vector, even though I believe I have enabled it.

The ISR is defined in my code as follows:

ISR(TCC0_OVF_vect)
{
TimerComplete(); //never goes here!!!
}

I'm using a JTAGICEII.

Please advise if anybody is aware of problems with using the "ISR" macro for the GCC toolchain for the xmega256a3b? If I am missing something in the interrupt config? or if the vector defines in the header file are incorrect?